bpo-45434: pyport.h no longer includes <stdlib.h> (GH-28914)

Include <stdlib.h> explicitly in C files.

Python.h includes <wchar.h>.

Include/Python.h

@@ -33,7 +33,8 @@
 #  include <stddef.h>
 #endif
 
-#include <assert.h>
+#include <assert.h>               // assert()
+#include <wchar.h>                // wchar_t
 
 #include "pyport.h"
 #include "pymacro.h"

Include/internal/pycore_fileutils.h

@@ -88,6 +88,9 @@ extern int _Py_add_relfile(wchar_t *dirname,
 //      ...
 //      _Py_END_SUPPRESS_IPH
 #if defined _MSC_VER && _MSC_VER >= 1900
+
+#  include <stdlib.h>   // _set_thread_local_invalid_parameter_handler()
+
    extern _invalid_parameter_handler _Py_silent_invalid_parameter_handler;
 #  define _Py_BEGIN_SUPPRESS_IPH \
     { _invalid_parameter_handler _Py_old_handler = \

Include/pyport.h

@@ -205,8 +205,6 @@ typedef Py_ssize_t Py_ssize_clean_t;
  * see https://bugs.python.org/issue28126 */
 #define Py_MEMCPY memcpy
 
-#include <stdlib.h>
-
 #ifdef HAVE_IEEEFP_H
 #include <ieeefp.h>  /* needed for 'finite' declaration on some platforms */
 #endif